This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The objective of this project is to develop a validated macaque model for sexual transmission of HIV by intravaginal (ivag) and intrarectal (ir) routes using a well-characterized RT-SHIV containing the RT of HIV-1. The rationale and significance of this project are described in the "Background and Significance" section. Considering the budget restriction, this project will focus on an ivag transmission of RT-SHIV in cynomolgus macaques (Macaca fascicularis). We will determine the virus-dose response to systemic infectivity after ivag exposure. The primary parameters of infection will include viral RNA, viral DNA and infectious cells in peripheral blood and the mucosa of the ectocervix, vagina, rectum and gut. We will characterize the nature of systemic and local infection of RT-SHIV in peripheral blood and mucosal surfaces of vagina, ectocervix, and rectum (by periodic lavage) and small intestines (at necropsy) and surrounding lymph nodes. These secondary parameters of infection are to identify the infected cell population and accessory factors (i.e. cytokines and chemokines which facilitate virus infection) at different mucosal sites: ectocervix, vagina, rectum and small intestine (jejunum and ileum). Additional secondary parameters of infection are to compare mucosal and systemic immune responses to RT- SHIV;so we will measure titers of SIV-antibodies in vaginal and rectal secretions and in serum obtained from peripheral blood, and detect specific antibodies to viral proteins produced in mucosa and/or serum. In summary, the objective of this study is ultimately to develop the successful RT-SHIV infection model in the cynomolgus macaque by vaginal transmission. Moreover, this established RT-SHIV macaque model will be useful for the efficacy evaluations of not only NNRTI-based microbicide candidates but also NNRTI and NRTI for systemic chemotherapy.